Is this the right time to start?" This is the most common question I hear from people flirting with the idea of entrepreneurship. The short answer: If you need to keep asking, then "NO". The best entrepreneurs are probably the ones for whom the term optimism bias was first coined. They don't sweat the details. They are confident about figuring things out as they go along.

When a company succeeds, they are often called visionaries. Otherwise they are called dreamers. A lot of it is hindsight.

Just to be clear, VCs like optimism. When you work with early-stage start-ups (like Pentathlon's portfolio companies) there's very little data to make any reliable predictions. The founder's optimism and confidence is the only thing we have to go on. So optimistic entrepreneurs are great! That said, there's a time when optimism begins to enter the territory of overconfidence. This usually happens in the growth stage, when there's a little more data coming in and you choose to ignore it. Take start-ups with ambitious plans but a runway that's rapidly running out. Here, simply being optimistic isn't enough. You need a plan of action.

Here is what founders can do so their optimism remains their advantage, instead of working against them.

1. Set timelines and retrospectives: Adding timelines to your proposed plan of action will help you get more clarity about your progress. Breakdown the plan into monthly or quarterly chunks. This can help you course correct when necessary.

2. A critical outsider. 90% of start-ups fail — we hear this at every turn. But every entrepreneur thinks they are going to be part of the 10% that make it. The 'x' factor is their own hard work and ability. This is expected. But having a mentor or critical outsider pitching your own ideas back to you can have a sobering effect. Your task is to be as critical as possible and predict failures or challenges the plan might face.

Some final thoughts — asking entrepreneurs to stop being optimistic is to ask someone to stop being themselves. In every instance, perseverance and grit is what sets them apart. That said, aligning your optimism to practical realities doesn't mean you've given up. Sometimes, it's what marks the start-ups that make it from the ones who don't.